Tacheometric telescope



` n Patented Jan. 13, 1931 'UNITED s'ra'rlazs'A Joann' ennn, or Eamonn, GERMANY, Assrerr'onfroL THE-fran cam. znrss, er w Y' JENA,GERMANY e i 'mcnnonnrnre *'rELscornj i application mea February 4, 1929, serial No. saute, 'andan Germany reruary '9, 192s.y

The invention relates to a tacheometric telescope and consists therein that such telescope is connected with a double-angled'prism serving the purpose of finding the foot ofthe perpendicular dropped from any point on the connecting line of two polygon points. The

new devicerenders feasible in a simple way the measuring of the ordinates in short range surveying according to the method of the right-angled co-ordmates for which purpose up to the present tape and measuring stave were applied.

The arrangement is suitably made in such i' a way that the double-angled prism is sup- .to rigidl I manner t I able, whereas as tac orted b the tacheometric telescope, where` y, for t e sakegof making the construction as simple as possible, it is further advisable connect the two parts in such a at the aiming line of the telescope is lying, onone hand, approximately in that plane to which the two prisms of the double angled prism are lying s mmetri'cally'and is,

on the other hand, aral el `to the main intersectingplanes of t e prism. As double-angled prism the well-known arrangement consisting of two pentaErisms is special'lysuitcometer appropriately one of the well-known double-image tacheometers is applied. The' foot of the telescope is conveniently given such a'form that a turning of the telescope/by 90 is made noticeable by notches.

Figures 1 to 3 of the drawing show a con-l structional exam le of the invention. Fig. 1 is-a vertical sect1on through thefoptical axis of the tacheometric telesco e, Fi 2 is a plan View, and Fig. 3 a lateral v1ew. ig. 4 serves the purpose lof explaining the surveying method 1n question.

By a stave athe axis X--X of which is supposed to be perpendicularly adjusted, a

tacheometric telescope b is supported on its foot b1 in the followlng manner: In a sleeve d which can be clamped tight byla set screw @and is rotatable on the axis X'X of the perpendicular stave a, there is rovided a lock f which is slidable perpendicu arly'to the axisX-QX and can be made to catch in one of the three notches b2 of the foot b1 when the telescope is turned on the axis X`X and of 90 one from another. V e contains anobJectrve'b; a collective` b, av reversingjlens, b5 and an eyeplece 6., From' notchesb'f always two are placed ataangles that side :of the ob'ectivebV which is facing the* collective .f' t erey are ground out two The telescope b lthe Saavedra maxed pqsitipimfwhich plane surfacesl and b of'which the common intersectingline bfdis lyingin the focal plane ofthe telescope `b and at the Sametime is parallel to the aXis X-X`and is intersecting theoptical axis Y-Y of` he telescope. With regard to the 4plane determined `by-this 1n;A i

tersectingiline and the optical yax-is"` of.1the

telescope, these l two surfaces are symmetric and have such an inclination to the said plane thatjthe, two yequal images of the `entrance pupil lying" nex'tto the reversing Prismbare b3 which, seen freornythe surveyor at the eyel piec'efb", is the oneto the right, a wedge f b1? isarranged 'in su'cha mannerthat the rays entering this lhalf are deflected gparalleltoI the intersecting linel'n"4 of the two wedge sur-k` faces b" and blof the' collective`b f i ,f l

The effect' of the delection yis shownk in Fig.' 3. The telescope aiming at a stave,gthe

surveyorkwill see two'i'm'a'ge's E andF ofthe stave, which areseparated'fr'o'm each other by a sharp division line. The product of the reciprocal distance vfrom each other ofthe images fof one andthe same graduatio'nfline ofthe stave and a constant peculiar tothe telescope gives the distance of the stave! from A theplace of the telescope. v

` On the telescope Ib two pentaprismsgfand h Aare ktightly arranged one above the other y sir'x1ilar'tol a ldoubleangled prism .such a way that'th'e'planeto which the two prisms have a symmetric' position, onv one hand conf..v

tains the turning axis X-X and on the other handthe optical axis Y-Y ofthe telescope b; Consequently,- theray entrance surface gl'of the lower prism g and the ray entrance surface kf of the upper prism h are paralleln to this plane, whereas the ray outlet surfaces g2 and h2 of the prisms are in a. common plane which is perpendicular to the optical axis Y-Y of the telescope b. In the upper 5 prism la, on its upger bounding surface la', there is milled a c annel in such a way that an aiming line is given which is parallel l to theo tical a'xis Y-Y of the telescope b and at t e same time intersects the turning m axis X-X of the telescope.

The application of the device is the following: Measuring staves having been erected c on the two end points A and B of a base line AB. and on a point C of which t-he rightangled co-ordinates should be determined,

and the foot b1 of the telescope b having been turned in the sleeve in such a way thatl the locky f has been caught in the middlefone of the three notches of the, foot b1 of the 0 telescope, the perpendicular rod a, the set t screw having been loosened previously, is to y Y lbebrought into such a position and the s leeve d turned in such a wayto the perpendicular stave a that (compare Figures 3 and 4) the image A1 of the stave erected on. A, whichwill present itself'to the surveyor through prism h and the image B1 of the stave erected von 13,5 which Will present itself to the surveyor through prism g, as well as thestave 3| 1 erected on C which is seen direct above the prisms, are in one straight linewhich perpendicularly intersects the channel L. Then, the axis X-X of the perpendicular stavea contains the foot D *of the perpendicular from 3;-, C on AB and the telescope 1s aiming at the stave'C1. The v telescope being in this osi-l tion, the set-screw c is to be fastened. v T ereupon, by means of the telescope the meas- Q uring of the ordinates CD has to take place. 40 This done,the telescope must be turned in counter-clockwisel direction in thesleeve d in such a manner that the 'lock f will catch Y. p i in one of the two notches b2 whereupon the f telescope is aiming at the stave erected on point A and, now the abscissa AD is to be measured. When the telescope is turned again and that by 180 in the sleeve d, the lock will catch in th third of the three. notches b2 and thetelescope is aiming at the 5o stave erected on point B and, now, the measuring of the abcissa BD has to be done. l I claim:l n

A tacheometric telescope, two angular prisms arranged one above the other on the telescope, each'of the prisms being adapted to deflect by "V a ray passing through it,l the ray inlet surfaces of the two prisms being parallel to each other and constituting faces opposite to each otherand lying parallel un to the optical axis of the telesco e and means to connect the two .prisms tigllit y witlrthe telescope;V e y JOSEF GRNE. 

